Fiber processing unit



Nov- 17, 1959 HOWELL I 2,912,722

FIBER PROCESSING UNIT Filed May 15, 1957 INVENTOR. EMORY L. HOWELL mww,

ATTORNEY United States Patent FIBERPROCESSING UNIT Emory L. Howell,Greenville,

S.C., assignor to The Dayton Rubber Company,

Dayton, Ohio, a corporation of Application May 15, 1957, Serial No.659,304 v9 Claims. (Cl. 19-131 individual fibers are tightly compactedand twisted so as to impart considerable tensile strength to the strand.The drawing or drafting of the fibers is generally achieved by passingthe same'through a series of pairs of nearly tangentially contactingrollers and/or aprons, the peripheral speeds of which increasesuccessively throughout the series so that those pairs which are forwardor in the direction of the travel of the roving will tend to pull anddraw out the strand while the rollers and aprons rearwardly thereof willact as a brake thereon.

In most of the drafting systems currently in use such as theWhitin-Casablancas and the Saco Lowell-Roth systems, at least one, apronin the form of a flexible sleeve having an outer fiber contactingsurface is employed. Such aprons are motivated by a powered roller indriving contact with the inner surface of the sleeve at the rearthereof. To provide a .planar apron surface for contacting the fiber, asupporting rod often referred to as a nose bar is employed to hold theapron at the front so that the normally cylindrical sleeve is held inelongated position during its travel about the driving roller and thenose bar. The nose bar itself is stationary and is so contoured andpolished that the apron will slide readily thereover. In the SacoLowell-Roth system, the tension of the apron is controlled by an idleror tension roller which usually rotates against the outer,fiber-contacting apron surface and urges it inwardly between thedriving,

roller and the nose bar.

Because the outer, fiber-contacting surface of the apron must be of acarefully controlled resilience and modulus of elasticity so as to exertthe proper pressure and grip upon the fiber being processed and becausethe inner surface of the apron must be carefully controlled as toresilience and friction properties so as to be properly driven forsmooth operation about the various rollers and apron supporting bars,the material of which these apron surfaces are composed must becarefully selected. In the.

early stages of the development of fiber processing, it was'the commonpractice to form drafting aprons of leather processed in various ways asby impregnation with oil and the like to control its surfacecharacteristics.

More recently however, it has been found that rubber.

and the various synthetic elastomeric materials such as synthetic rubberand particularly the copolymers of buta- 'diene and acrylonitrileprovide improved drafting characteristics over a greatly extendedoperational life. Other synthetic plastic materials which have beenadvantageously employed in either the inner or outer apron surfaces haveincluded other synthetic rubbers such as the butadiene-styrenecopolymers, 'the polychloroprenes, polysulfides, and other synthetic,elastomeric plastic material such as the polyurethanes,polyamides,polyvinyl chlorides and the like as well as mixtures of thesevarious materials.

in the case of all of the many synthetic materials and mixtures thereofwhich have been employed in fiber drafting aprons however, there has,for some unexplained reason, been a marked tendency for the accumulationof lint about certain of the drafting machinery parts. In both the SacoLowell-Roth and Whitin-Casablancas systems for example, the use of asynthetic material on either of the apron surfaces has resulted in anaccumulation of lint upon the nose'bar or apron supporting rod at eachedge of the apron passing thereover. The individual fibers continue tobuild up at these points on the nose bar until theiraccumulation. is ofsufiicient Weight that they will fall'ofii' "In many instances this massof loosely assembled fibers falls directly into the strand beingprocessed by the apron; and, since the fibers are so heterogeneouslyarranged, they cannot be properly drawn and aligned in the draftingprocess and will be only loosely associated even in the finished yarn.-Because these fibers are not drawn and spun they haveverylittle tensilestrength and constitute a weakening defect known as a slub.

Similarly, in systems such as'the Saco Lowell-Roth system employing.atensioning or idler roller in contact With one of the synthetic apronsurfaces, loose fibers tend to accumulate upon the surface of suchroller at the points where it is' contacted by the apron. As such fibersbuild up about the tensioning Tor'idler roller, they tend to increasethe effective diameter thereof with the result that the apron becomes.even further tensed orstretched; and in time the apron willtherebybecome so taut that it cannot slide freely over the nose bar orother supporting components of the fiberdraftingmachinery with theresult that the apronlwill Ibreak'or' bind to disrupt the draftingoperation long before the aprons would otherwise have failed.-- I T Itis accordinglyanobject of the present invention to It is a more specificobject of the present invention to provide'an improved apronhavingsurfaces of synthetic material for use in drafting. I

It is still a further object of the-present invention to provide adrafting apron for use in drawing machinery wherein the apron slidesover a stationary supportingrod or nose bar such as in theWhitin-Casablancas and the Saco Lowell-Roth systems or is contacted bya'tensioning or idler roller as in the Saco Lowell-Roth system;

It is still another object of the present invention to provide a fiberdrafting apron which will not result in an accumulation ofheterogeneously arranged fibers upon the drafting machinery parts incontact with such apron.

It is still a further object of the'present. invention to provide afiber drafting apron which will form a thread or yarn wherein all of thefibers are uniformly drawn and aligned. V v

Still another object of the present invention is to provide a method forthe manufacture of suchfiber drafting aprons. i I

These and other objects and advantages of the present invention whichwill beap parent from a reading of the following disclosure are achievedby forming theinwardly disposed surface of the apron of any of the aboveenumerated synthetic materials to obtainthe advantages, of each andknurling such surface by providing a plurality of protuberancesprojecting inwardly therefrom. In' the preferred embodiments of thisinvention hereinafter described, these protuberances are preferably inthe form of raised ribs or ridges of relatively small cross section andrelatively closely spaced. While such ribs may be according to a varietyof patterns, it has been found that definite improvements are achievedwhere the ribs are in parallel relationship extending transversely,longitudi nally or diagonally of the apron sleeve about its innersurface. An even more pronounced improvement over the prior art deviceshas been achieved Where the ribs rising from the inwardly disposed apronsurface are of two classes, those ribs in each class being in parallelrelationship diagonally of the sleeve and intersecting the similarlydisposed ribs of the other class. It has been found that thiscriss-cross arrangement of the parallel ribs of the two classesintersecting to form a diamond-like pattern about the entire innersurface of the apron has been capable of almost completely eliminatingany accumulation of loose fibers upon the fiber working machinery wherethe ribs of both classes of ribs intersect the longitudinal axis oredges of the apron at an angle which is less than 45 whereby thediamonds will be elongated in a direction transversely of the apronsleeve.

The invention thus generally described may be more clearly understoodfrom the following detailed descrip tion of certain preferredembodiments thereof in connection with which reference may be had to theappended drawings.

In the drawings:

Figure l is a diagrammatic view of a fiber drafting apron according tothe present invention employed in the Saco Lowell-Roth fiber draftingsystem.

Figure 2 is a fragmentary perspective in partial cross section of onepreferred form of drafting apron according to the present invention.

Figure 3 is a plan view of the inwardly disposed surface of stillanother preferred apron according to the present invention.

Figure 4 is a similar plan view of the inwardly disposed surface ofanother apron according to the present invention.

Figure 5 is a perspective of a building mandrel for use in themanufacture of fiber drafting aprons according to the present invention.

Referring now to Figure 1, the strand or sliver 1 1 is shown to bepassing through the bite of the rear drawing rollers 11 and 12, alongthe fiber contacting surface 1.: of the drafting apron 14 and thenthrough the bite or mp of the front drawing rollers 15 and 16. Thestrand 10 may be held against the drafting surface 13 of the apron byintermediate rollers such as 17 and 18.

The drafting apron 14 forming the subject matter of the presentinvention is in the form of a flexible sleeve WhlCh would be normallycylindrical but is held in an elongated or extended position by means ofthe rollers 19 and 20 and the nose bar or forward supporting rod 21,these components being so spaced that the apron assumes the generalshape of a triangle in passing around them. In the Saco Lowell-Rothdrafting system of which Figure 1 is a diagrammatic illustration, theapron 14 is usually motivated by its contact with the roller 19 which isitself rotatably driven by suitable connection to the power or drivingcomponent of the drafting machinery. The guide roll 20 is rotatablymounted to be freely driven by the apron passing thereover, and the nosebar 21 is stationary. The apron slides over the nose bar which is smoothand polished at least at those surfaces which are contacted by theapron. To control the tension of the apron as it is supported by therollers '19 and 20 and the nose bar 21 is the tension or idler roller 22which is also mounted to rotate freely with the moving apron. Theposition of this roller 22 however, is controllably adjustable so thatit may displace the apron from its normal path between its supports toachieve the desired tension for enabling the apron to maintain drivingcontact with the roller 19 and at the same time to pass smoothly overthe guide roller 20 and the nose bar 21.

As explained above, it has been the problem in the case of all of themodern aprons of synthetic material that, as the apron continues tooperate, loosely associated fibers begin to build up upon the surface ofthe nose bar 21 adjacent the edges of the apron and upon the parts ofthe idler roller 22 in contact with the apron. It can be seen that thefibrous mass accumulating on the nose bar is dangerously close to thesliver or roving being processed and could easily be drawn into thesame. On the other hand, it can be seen that, as fibers build up uponthe idler roller 22, the effective circumference or diameter of thisidler roller will be increased so that it will displace the apron morethan was desired or contemplated by the selective adjustment of theidler roller. As the apron thereby becomes increasingly tensed orstretched, it will either bind in passing about the rollers 19 and 20and the nose bar 21 or will actually break. When the apron binds, notonly will the drafting operation be disrupted but also the apron will beseriously damaged by the driving roller 19 which will continue to rotateagainst one portion only of the apron causing excessive wear at suchpoint.

In order to solve these difficulties, the apron of the present inventionis provided with a knurled or roughened inwardly disposed surface 23which is characterized by a plurality of protrusions such as 24projecting inwardly therefrom. 'Ihese protrusions may be in the form ofribs extending across the inwardly disposed surface 23 of the apron. Asbest shown in Figure 2, the ribs on the inwardly disposed surface 25 maybe divided into two classes respectively designated by the numbers 27and 28 wherein the ribs in each class are in parallel relationshipdiagonally of the apron and intersect the ribs of the other class whichare similarly disposed. This intersection of the spaced, parallel ribs27 and 28 respectively, results in the formation of a diamond patternabout the entire inner surface 25. Where the ribs of each classintersect the longitudinal axis or the edges of the apron at an anglewhich is less than 45, the diamonds 29 formed by their intersection willbe flattened or elongated so that their greatest dimension extendssubstantially transversely of the apron sleeve. It will be noted thatthe ribs of both classes 27 and 28 intersect the edges or thelongitudinal axis of the apron at the same angle so that the diamonds 29are symmetrical about their longitudinal and transverse axes which arerespectively longitudinally and transversely aligned upon the apronsleeve.

The ribs 27 and 28 are formed of the same material as that comprisingthe inwardly disposed surface 25 of the apron which in turn may be thesame as or at least similar to the material of which the rest of theapron is composed. While, for the sake of clarity, the ribs have beenshown to be relatively large, they are in fact of small cross sectionand where, for example, the over all apron thickness is on the order of.032 inch, the ribs themselves may measure approximately .005 inch orless in cross-sectional width and height. In one preferred embodiment ofthe present invention, it has been found that the ribs in each of theclasses 27 and 28 may be spaced by from to of an inch; and in the caseof an apron .032 inch thick wherein the ribs are .005 inch in height andwidth, a rib spacing of of an inch between centers has been found toprevent the above described undesirable formation of loose fibers eitheron the idler roller such as 22 or along the nose bar 30 at the edges 31and 32 of the apron shown in Figure 2. One preferred angular dispositionof the ribs so arranged has been found to be that which will result inthe formation of diamonds which measure approximately 1.75 millimetersin their longer, transverse dimension and approximately l millimeter intheir shorter dimension longitu' dinally of the apron.

In lieu of the criss-cross or intersecting ribs illustrated in Figure 2,it has been found that n'bs arranged in parallel and extending generallytransversely as are the ribs 33 of the apron 34 in Figure 3 or extendinglongitudinally as are the ribs 35 of the apron 36 of Figure 4 will alsosubstantially reduce the accumulation of fibers at the objectionablepoints in the fiber drafting machinery when an apron of syntheticmaterial is employed.

Aprons according to the present invention may be formed in theconventional manner as for example that described in the United StatesPatent No. 2,341,656 issued February 15, 1944, to Joseph Rockoflf,wherein the layer or layers of synthetic material to form the apron bodyare wound about a mandrel and then compacted prior to vulcanization andfinal treatment. The ribs according to the present invention may beconveniently provided in such a method by employing a building mandrelhaving grooves or depressions therein corresponding to the protrusionsor ribs ultimately desired in the finished apron. Such a mandrel isdesignated by the number 37 in Figure 5 wherein the outer periphery orbuilding surface 38 is shown to have formed thereon a plurality ofgrooves 39 so arranged that when the grooves are filled with theelastomeric material forming the innermost apron surface, a ribbedsurface similar to that illustrated in Figure 3 will result. The patternof the grooves 39 may of course be altered to achieve either of the ribpatterns shown in Figures 2 and 4 or any other desired arrangement ofribs or other protrusions. It will be understood that where avulcanizable rubber or any other plastic elastomeric material isemployed in the apron and particularly upon the innermost surface thereof, such material may be brought to a state of plastic flow whereupon itmay be molded to assume the surface characteristics of the mandrel andthereafter allowed to set so that such characteristics will bepermanently fixed in the finished apron.

While the present invention has been described in considerable detail inconnection with certain preferred embodiments, it is to be understoodthat such particul-arization and detail have been for the purpose ofillustration only and do not limit the scope of the present invention asit is defined in the subjoined claims.

I claim:

1. A fiber drafting apron in the form of a flexible sleeve having anoutwardly disposed fiber-contacting surface and an inwardly disposedroller and nose bar contacting surface wherein said inner surface has aplurality of small parallel ribs extending longitudinally of said sleeveand projecting inwardly therefrom.

2. A fiber drafting apron in the form of a flexible sleeve having anoutwardly disposed fiber-contacting surface wherein said inner surfacehas a plurality of small parallel ribs extending diagonally of saidsleeve and projecting inwardly therefrom.

3. A fiber drafting apron according to claim 2 wherein said ribs aredivided into two classes, the ribs of one class intersecting those ofthe other class forming a diamond pattern of ribs about said innersurface.

4. A fiber drafting apron according to claim 3 wherein said ribs formangles of less than 45 with the longitudinal axis of said sleeve.

5. A fiber drafting apron according to claim 4 wherein all of said ribsare disposed at an angle which is less than 45 to the longitudinal axisof said sleeve whereby the greatest dimensions of the diamonds formed bysuch ribs extends transversely of said sleeve.

6. A fiber drafting apron according to claim 5 wherein the ribs arespaced by from to V of an inch.

7. A fiber drafting apron according to claim 6 wherein the ribs in eachof said classes of ribs are spaced by a distance of ,6 of an inch.

8. A fiber drafting apron according to claim 6 wherein said ribs aresubstantially .005 inch in height and width.

9. A fiber drafting apron in the form of a flexible sleeve having anoutwardly disposed fiber-contacting surface and an inwardly disposedroller and nose bar contacting surface wherein said inner surface has aplurality of small parallel ribs projecting inwardly therefrom andforming angles of less than 45 degrees with the longitudinal axis ofsaid sleeve.

References Cited in the file of this patent UNITED STATES PATENTS1,028,783 Von Rabenau June 4, 1912 1,799,448 West Apr. 7, 1931 2,054,619Freedlander Sept. 15, 1936 2,341,656 Rockoff Feb. 15, 1944 2,362,340Bacon Nov. 7, 1944 2,686,939 Keyser Aug. 24, 1954

